This is the Doppler effect.
1. As the sound leaves the horn the sound waves are at first close to each other and as they move outwards they become further apart. The closer the sound waves are the louder the noise.
As the car gets the closer the sound waves get closer, so the horn becomes louder.
2. As the horn moves away, the sound waves become less frequent, causing the pitch to get lower.
True mechanical advantage of a machine is always greater than
Answer:D: the velocity is zero
Explanation:
The precipitate is the barium sulfate, or 3) BaSO4. This is because it is a solid (as seen by the (s)), unlike the other aqueous product. The fact that it is a solid means that it is insoluble in water and therefore a precipitate.
Hope this helps!
